The regulation of diesel emissions is becoming more and more stringent. The need for better closed loop control will be necessary in the future in order to meet the more demanding standards and on board diagnostics (OBD). One way in which the regulation of diesel emissions can be improved is by utilizing an NOx sensor system. A typical NOx sensor system consists of a sensor and sensing electronics box. The sensor is mounted in the exhaust in such a way so that it can measure the amount of NOx concentration in the diesel emissions and then send that information to a sensing electronics box.
As the sensor ages over time, the sensor changes such that the actual NOx concentration in the exhaust is different than NOx concentration measured by the sensor. This change is typically caused by fouling of the sensor's catalytic material.
Accordingly, what is needed is a system and method for compensating for the change is sensitivity of the NOx sensor, thereby both extending the useful life of the sensor and also providing more accurate readings during the life of the sensor. The present invention addresses such a need.